A toy is well known which enables a child to make a desired design, figure or picture by mounting blocks of desired shapes and colors in cells. With such a toy, children not only may amuse themselves looking at their products, but also may develop their artistic sentiments through producing desired artworks. In many of the conventional toys of this kind, however, the blocks are prone to be easily removed from the cells if the support in which the cells are formed is vibrated or is given an impact.